Since the beginning of time, human beings have sought improved materials for shelter. Most of what was used thousands of years ago is still in use today, in one form or another. For example the stone used in caves is used as slate roofing or granite walls. Mud is transformed into bricks and leaves are used in thatch roofing. Modern cladding originates from one form of or a combination of very basic materials.
The historic benefits of stone, metal and tar don't come without some drawbacks. For example stone, including slate and granite, is very durable and resistant to the sun's ultraviolet UV rays but it is also very heavy and rigid. Metal such as copper and aluminum is relatively lightweight and can be bent into any shape but installation can be very specialized and the resulting structure is susceptible to condensation leaks. Tar including bitumen and asphalt is also lightweight and very waterproof but does not last very long in the sun and has very little body so that it is flimsy to handle. Improvements have been made by modifying or combining the materials with each other.
Asphalt shingles, by far the most popular roof cladding in North America, is basically tar and gravel supported by saturated felt. The stone granules in the gravel delay deterioration of the tar from UV rays and the tar holds the granules in place. Although this is a great innovation, the effect of the UV rays on the tar is not eliminated and the asphalt shingles eventually do shed their granules, curl, crack and lift from the underlying wood panels, and although they are laid in an overlapping manner, the shingles need to be replaced. Depending on the thickness of the shingle, and the trend has been towards thinner shingles, it is generally recommended to replace the roof shingles every ten to fifteen years.
Metal tiles are becoming more popular. However, they still suffer from the drawback that they are expensive because of the cost of the tile itself and also the complexity of installation and warehousing. Suitable metals for use in roof tiles are galvanized steel, aluminum, zinc or copper. Another disadvantage is that snow and ice easily slide off a metal roof and this creates a potential hazard to persons walking or working adjacent to the building or home and can destroy property such as eavestroughs, lower roofs, decks, vehicles and the like. For occupants of the home, the noise from rain falling on the roof can also be disturbing and condensation problems have also been observed. Another disadvantage is that smooth metal has a commercial look and the color will fade when exposed to UV rays.
One solution to these problems has been the application of a simulated stone covering to the metal tile. This reduces noise transmission to the interior of the building structure, restrains movement of snow and ice, remains colorfast and more residential in appearance. This process has improved since its start in 1956 and is now accepted as a proven process worldwide. A series of recent patents issued to BASF Corporation, including U.S. Pat. No. 6,540,829 provide a system for coating sheet metal coil with a resinous composition and embedding granular material in the wet surface of that coating to simulate the appearance of a traditional mineral covered asphalt shingle.
US 2002/0116886 provides a simulated wood shake made of metal which has a stone-chip coating to form a pattern of differently colored areas, the areas being coordinated with alternating raised and lowered sections of the metal roof panel. The product is a successful simulation of wood shakes but it is still expensive and difficult to install primarily because the metal needs to be sufficiently thick to maintain its shape under pressure and specialized installation accessories are required.
Another stone coating innovation is an exterior cladding consisting of a mixture of stone granules in an acrylic resin which is applied on an exterior wall system using a trowel. This demonstrates the use of synthetic adhesives to replace tar, and results in a cladding which is more resistant to UV rays.
A foil faced bitumen products is currently available and sold in association with the trademark Tegola®. This allows the cladding to be made thinner and easier to apply to a roof deck surface while giving it a protective layer of metal so that it can last longer. An exemplary description of a metal clad asphalt shingle is provided in U.S. Pat. No. 3,607,529 issued to Alcan Aluminum Corporation in 1971. One problem with this shingle is that the metal covers the whole of the backside, eliminating the sealing qualities of the tar. Another problem is that the weak unprotected metal foil is easily susceptible to scratches, puncture, tearing, fading and delamination.
Applicant is aware of only one attempt at combining stone, metal and tar to produce a superior cladding laminate. This was a New Zealand roof tile consisting of stone granules imbedded into a bitumen-based adhesive originating from a WWII British innovation branded as Decramastic and applied to a metal panel. These were supposed to last a lifetime. Instead, the granules would shed after only a few years. As a solution, the bitumen was eliminated and replaced with acrylic. The concept was to protect the metal, which was primitive galvanized steel sheets which had a tendency to rust easily from scratches and simple elements with a bituminous coating. The stone chips were only introduced by chance, and not for their UV resistant qualities, when sand was applied to the bitumen to solve the problem of panels sticking together in the shipping. When the aesthetic qualities of the sand were noticed, they began to use color co-coordinated natural stone chips. Although stone-coated metal is a great innovation, it still relies on the thickness of the metal for structural strength, walkability and water tightness.
An object of this invention is to provide an improved exterior cladding laminate which combines the beauty and protection of stone with the durable and preserving qualities of metal and the water repelling qualities and easy installation of tar including asphalt and bitumen. Significant material cost savings also may be achieved by selecting thinner and lighter materials which also makes the product easier to handle, cut and install hence also reducing installation costs.